It is well known that when treating chronic and acute wounds like venous stasis ulcers, pressure sores, open surgical wounds and burns it is a primary goal to reduce the healing time. Speeding-up of the healing may be obtained by cleansing and debriding of the wound combined with an effective removal of wound exudate. Commonly used wound dressings comprise gauze, foams, sponges, cotton pads or other fibrous materials. Gauze and other fibrous materials may absorb fluids by capillary action but implies, however, the disadvantages that fibres of the gauze or other fibrous materials may adhere to the new tissue causing damage to the newly formed tissue when removing the gauze or fibrous material causing wound injury on removal.
Amorphous hydrogels is a category of products used for debridement. These gels function by keeping the wound moist and thereby enhancing autolytic debridement of necrotic tissue by enzymes generated in the body by e.g. inflammatory cells.
A too aggressive debridement can impair the healing as some of the active components may be cytotoxic. Furthermore, other ingredients of a gel, e.g. preserving agents or active agents or other constituents may also be cytotoxic and may hamper the healing.
Often polyols are used for amorphous hydrogels as bacteriostatic agents, but are known for being potential allergenic, see e.g. Journal of Pharmaceutical Sciences 1990;79:312-316, Arch Dermatol. 1979;115:1451, CUTIS, 1978;21:166-178, and Contact Dermatitis 1980;6:341-144.
EP 0 567 311 A2 discloses a hydrocolloid wound gel composition which is stated to cleanse and debride wounds and to have some exudate absorbing capacity, said gel containing from about 0.005% to 1.0% by weight of a pectin, from about 2.0% to 4.5% sodium carboxymethylcellulose, from about 15.0% to 20.0% by weight of propylene glycol and the remainder substantially water to make 100% by weight.
EP 0 576 523 B1 discloses a wound dressing comprising a gel containing a water-insoluble, water swellable cross-linked cellulose derivative, water and a polyol component wherein the cellulose derivative comprises less than 10% by weight of the gel. The dressing may contain additional debriding agents, e.g. enzymatic debriding agents and/or growth factors.
EP 0 512 855 A2 discloses an absorbant wound filler comprising a polymeric matrix containing one or more styrene radial or block copolymers, one or more polyisobutylenes and mineral oil and absorbing powders comprising sodium/calcium alginates, optionally cross-linked sodium carboxymethylcellulose, optionally absorbent polyacrylates and optionally water soluble hydrocolloids. The role of the matrix is to hold the absorbing powders and the polyisobutylene helps to bind the powders in the polymeric network and mineral oil is a plasticizer for the styrene radial or block copolymer component.
WO 95/17166 discloses a wound hydrating gel comprising a hydrocolloid system comprising carboxymethylcellulose, sodium alginate/calcium alginate and a preservation system in which is preferably used a self-gelling Na/Ca alginate having about 6-7% sodium minerals and about 2.5-3.5% calcium minerals.